Prognostic impact of cyclin-dependent kinase inhibitor p27kip1 in node-positive breast cancer

BACKGROUND AND OBJECTIVES: p27kip1 (p27) plays an important role as a negative regulator of cell cycle-dependent kinase activity during progression of the cell cycle. The most important prognosticator of breast cancer is nodal status, and the aim of this study was to determine the prognostic implication of p27 in breast cancer patients with lymph node metastases. METHODS: Immunohistochemical staining for p27 was performed on tissues from 102 patients with node-positive breast cancer. RESULTS: A nuclear staining over 50% was defined as high expression. High expression of p27 was shown in 59 patients (57.8%). A significant correlation was found between high p27 and positive estrogen receptor status, but there was no correlation between p27 staining and age, menopausal status, nodal status, or tumor size. Low expression of p27 was significantly associated with shorter survival. A multivariate analysis also showed that the only independent variable was p27. CONCLUSIONS: The results indicated that low expression of p27 was an independent factor associated with poor prognosis. Therefore, p27 can be an important tool in making therapeutic decisions.